1. Field of the Invention
This invention relates generally to collapsible, self-supporting structures for displays, and more particularly to a hub assembly for pivotally holding the ends of the column-like support rods which make up the skeletal frames for such collapsible structures.
2. Background of the Invention
Collapsible structures are desirable for displays in situations where a display must be quickly erected and later collapsed. Such collapsible structures typically have a network of support rods pivotally joined together at hubs for movement between a collapsed, compact position for storage or transport and an open or erected position in which the desired structural shape is attained. Such a structure is disclosed in U.S. Pat. No. 4,658,560, issued Apr. 21, 1987 to Beaulieu and hereby incorporated by reference. This collapsible display panel includes a plurality of hub assemblies and a support and attachment brace. The support rods in these collapsible, self-supporting structures are pivotally joined by the hub assemblies. Collapsible, self-supporting dome or arch-shaped structures are disclosed by U.S. Pat. Nos. 3,838,703, 3,968,808, 4,026,313, and 4,290,244, the disclosures of which are hereby incorporated by reference. Collapsible display panel or wall structures with planar or arcuate face surfaces are disclosed by U.S. Pat. Nos. 4,276,726, and 4,471,548, the disclosures of which are hereby incorporated by reference. These collapsible display panel structures are typically covered by a sheet of material adapted for either covering the front of the panel structure or displaying a graphic representation thereon. U.S. Pat. No. 4,471,548 teaches attaching the sheet to the structure by cooperating Velcro(trademark) and magnetic strips and corresponding hole and male fastener arrangement.
A hub assembly for a collapsible structure is disclosed in U.S. Pat. No. 4,627,210 issued Dec. 9, 1986 to Beaulieu and hereby incorporated by reference. This hub assembly pivotally holds the ends of column-like support rods, which make up the skeletal frame of a collapsible, self-supporting structure. The hub assembly includes extension caps for the ends of the support rods and a circular hub body with retaining slots or sockets, which receive and pivotally hold spherical heads of the extension caps. A circular locking disk releasably interlocks with the hub body to retain the ends of the extension caps in a pivotal relationship within the hub body. A bayonet with protrusions or knobs extends from a bottom face of the disk. The bayonet snap-locks in place to retain the extension cap spherical heads within hub body sockets. These hub assemblies interconnect support rods in a generally uniplanar pivoting relationship. One disadvantage is that if the knobs or male snap fasteners on the bayonets become worn or loose, the locking disc is likely to either loosen or become detached from the hub body. Loosened or detached locking disks may, in turn, cause the interconnected pivoting rods to become to loosely held in the hub or may collapse the structure. Moreover, this hub assembly may be more difficult to repair than desired at times. For instance, all eight support rods must be held in position when a locking disk replacement is snap-locked back in place.
U.S. Pat. No. 4,986,016, issued Jan. 22, 1991 to Wichman and hereby incorporated by reference, discloses a folding display frame with an off-set hub configuration. The collapsible framework disclosed therein is constructed of rods pivotally joined at their ends to hubs to form a self-standing unit when expanded and folding into a small set of nearly parallel rods. The expanded frame forms an array of cubicles. The hubs are designed to pivotally join the ends of four rods, with the plane defined by the pivot axes of one pair of opposing rods being off-set from the plane defined by the pivot axes of the other pair of opposed rods attached to the same hub such that the bearing surfaces of each are coplanar. One pair of rods attached to each hub can pivot on one of several pivot points on extended hub flanges, thereby providing expanded frameworks of various arcuate configurations. A stab-connection latch locks two hubs together and secures the framework in the expanded position. Folding channel bars are attached to knobs on vertically aligned hubs by key slots. The key slots of one channel bar are of progressively shorter lengths going from the top-most to the bottom-most of the vertically aligned hubs to which the bar is attached. The folding channel bars have adjustable friction-type hinge pins for controllably folding sections of the channel bars. However, repair of the display frame may be difficult. The hubs are not easily disassembled. Nor are the support rods easily separated from the hubs. Hence, extended periods of unavailability may result from difficult and time-consuming repair requirements of this display frame. Moreover, use of this display frame with damaged, worn, or otherwise defective hubs could create hazardous situations in which the erected frame could collapse. Additionally, the hubs discussed hereinabove usually include structures with metal-to-metal movement, thereby further effecting excessive wear and causing unsightly appearances.
The present invention provides a hub assembly for pivotally connecting the ends of support rods of a self-supporting structure. The self-supporting structure may be configured for a collapsed storage position and an expanded display position. The hub assembly may include a first base portion, a second portion, and an optional connector pin. The first hub base portion may include a plurality of axially extending first extensions, and the second hub portion may include a plurality of axially extending second extensions. The first and second extensions may be generally U-shaped in cross-section and when assembled define rod receiving sockets. The base may include a generally central axial opening and the second member may define an axial opening generally coaxial with the opening in the first member. The first and second members are generally matable along inboard surfaces and a connector may be configured to extend through the openings in the first and second members to secure the hub portion together.
Another significant feature and advantage of particular embodiments of this invention is that damaged hubs or rods may be easily field repaired with a minimal of expense and downtime.
A still further significant advantage and feature of particular embodiments of this invention is that portions of the hub assembly may be held together by way of frictional interlacing engagement and by way of a locking pin extending therethrough.
A yet further significant advantage and feature of particular embodiments of the invention is that the cooperating/mating hub portions, particularly the circumferentially interlaced portions, each provide complimentary structural support to the other.
Another feature and advantage of the invention is that the hub portions engage with one another to capture the rod ends within the hub.
Another feature and advantage of particular embodiments of the invention is that the hub portions can be easily injection-molded and the rod ends attached thereto without separate fasteners such as additional pins or rivets.
Another advantage and feature of the invention is that interlaced extensions define sockets for the rod ends.
A further advantage and feature of particular embodiments of the invention is that rods extending in opposite directions from each hub have their inner bearing surface slightly offset to accommodate a bearing spacer at the intersection of pivotally attached rods extending from adjacently positioned hubs.
A further object and advantage of particular embodiments of the invention is that a variety of retention means and rod end configurations may be utilized to retain the rod ends within the hub. These retention means can include pins integral, or fixed, to the rod end, or shaped rod ends, and removable pins. Each such retention means is accommodated by variations of the hub portions according to the invention.
Another object and advantage of particular embodiments of the invention is that the display frame work can be additionally assembled and repaired without the need for special tools and without destroying parts, i.e., rivets, during removal.
Another object and advantage of particular embodiments of the invention is that placement and repair parts may be kept by the user for instant repair in the event of a component failure.
An additional feature and advantage of particular embodiments of the invention is that the easily separated hub portions may be utilized to connect additional display frameworks or additional sections to an existing collapsible structure.